As the skilled ones in the art well know, the fluid circulation pumps arranged in the heating plants or systems are commonly referred to as “circulators”.
Current circulators are almost completely supplied with asynchronous motors. Circulators with synchronous motor having permanent-magnet rotor have become commercially successful only recently.
The most popular and cost-efficient synchronous motors only have two stator pole shoes; nevertheless four-pole shoes synchronous motors have been used in modern circulators so as to overcome vibration problems.
For example, a four-pole shoes stator synchronous motor for a circulator is disclosed in U.S. Pat. No. 6,452,303 to the same Applicant.
The stator described in the above-referred patent application is a simple, low-cost construction, each pole piece or pole shoe comprising a combination of a stator coil and respective core of laminations.
The core of laminations are E-shaped pieces cut off from the same metal sheet strip for reducing scraps, and they are overlapped and packed together into statoric group portions that also have an E-shape.
The stator coils are wound around spools by means of automated coil winders, having good return. Each spool includes a pair of connecting pins to which the opposed ends of the conductive wire wound around it are led.
Each spool is fitted on the central part of the E-shaped core of laminations, and the resultant pole shoes are laid adjacent one another to form a ring-like structure which is held together by springs that elastically tie the close ends of the E-shaped portions of the stator group to each other.
Subsequent steps in the motor manufacturing process include tinning and electrical connection of the connecting pins of the spools and their connection to conductive tracks of an electronic board.
While being in several way advantageous, the above assembly procedure is still inadequate for large-volume production methods and extensively automated assembling.
The aim of the present invention is that of providing a permanent-magnet synchronous electric motor, particularly for use with circulation pumps of heating systems, with a uniquely simple construction appropriate to improve the automation of the motor assembly procedures.